
ANNA-B4 series - System integration manual
UBX-21000517 - R03
Contents
Page 46 of 74
C1-Public
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If an external crystal or TCXO is mounted, the u-connectXpress software settings require a crystal
accuracy of 20 ppm or better.
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If no external crystal or TCXO is mounted, the u-connectXpress software uses the internal RC
oscillator with the settings of a calibration timer interval of 4 s and minimum calibration of 2
calibration intervals. This ensures that a calibration is performed at least once every 8 seconds
and for changes of temperature above 0.5 °C every 4 seconds. See also the nRF52833 product
specification